The present invention relates generally to assembly lines and conveyor systems, and, in particular, to a flange bearing for supporting a rotatable shaft.
In manufacturing, assembly lines and conveyor systems commonly utilize flange bearings to support cylindrical shafts upon which manufactured products are transported. The bearings are mounted to a support structure which forms a track or bed along which the products are conveyed. Each shaft is received in a bearing insert of a housing for the flange bearing. The flange bearing might comprise a square housing mounted using four bolts, one at each corner. Alternatively, the flange bearing might comprise an eye-shaped housing utilizing two bolts for mounting.
Cast iron was the common material used for manufacturing early flange bearing housings which were mounted by either two or four bolts. A solid body was formed which easily withstood the stresses imparted by the heavy and/or cyclic loads from the shaft supported therein. Further, the cast iron housing was usually either metal-plated or painted to resist corrosion from exposure to water, cleaning chemicals, spilled products or other contaminates, especially in the food processing industry. However, the housing exterior would eventually deteriorate or become unsightly, especially since stringent cleaning was required to meet sanitation specifications in the aforementioned industry.
A more recent type of flange bearing comprises an injection-molded plastic housing. In particular, if the housing is injection molded in the form of solid plastic, the housing would disadvantageously shrink and deform unpredictably upon cooling. In order to provide an injection-molded housing of the equivalent strength of cast iron with repeatable dimensional stability, it is necessary to increase the overall geometry slightly for strength and incorporate a ribbed structure for dimensional stability. The result is an "engineered plastic" housing providing the desired positional geometry incorporating ribs and cavities. In an engineered plastic housing, the ribs provide strengthening to resist stress fractures of the housing from the shaft loading, while maintaining the desired shape during the molding process.
In addition, the cavities of the engineered plastic housing are more difficult and time consuming to clean satisfactorily than a solid body housing. Plugs created to fill the cavities, thereby making cleaning easier, tend to settle after time and during temperature changes so that the outer surface of the housing body is no longer flush, and the same cleaning difficulties remain. Plugs are often made of a different material than the housing and consequently expand and contract at a different rate than the housing causing undesirable cracks, crevices and uneven surfaces.
In view of the foregoing, a need exists for an improved bearing housing that overcomes the problems mentioned.